/*
 * Copyright (c) 2001-2003 Swedish Institute of Computer Science.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without modification,
 * are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice,
 *    this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright notice,
 *    this list of conditions and the following disclaimer in the documentation
 *    and/or other materials provided with the distribution.
 * 3. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
 * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
 * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
 * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
 * OF SUCH DAMAGE.
 *
 * This file is part of the lwIP TCP/IP stack.
 *
 * Author: Adam Dunkels <adam@sics.se>
 *
 */

/* Some ICMP messages should be passed to the transport protocols. This
   is not implemented. */

#include "lwip/opt.h"

#include "lwip/icmp.h"
#include "lwip/inet.h"
#include "lwip/ip.h"
#include "lwip/def.h"

#include "lwip/stats.h"

#include "lwip/snmp.h"

#include <sysclib.h>

#include "smsutils.h"

void icmp_input(struct pbuf *p, struct netif *inp)
{
    unsigned char type;
    unsigned char code;
    struct icmp_echo_hdr *iecho;
    struct ip_hdr *iphdr;
    struct ip_addr tmpaddr;
    u16_t hlen;

    ICMP_STATS_INC(icmp.recv);
    snmp_inc_icmpinmsgs();


    iphdr = p->payload;
    hlen = IPH_HL(iphdr) * 4;
    if (pbuf_header(p, -((s16_t)hlen)) || (p->tot_len < sizeof(u16_t) * 2)) {
        LWIP_DEBUGF(ICMP_DEBUG, ("icmp_input: short ICMP (%u bytes) received\n", p->tot_len));
        pbuf_free(p);
        ICMP_STATS_INC(icmp.lenerr);
        snmp_inc_icmpinerrors();
        return;
    }

    type = *((u8_t *)p->payload);
    code = *(((u8_t *)p->payload) + 1);
    switch (type) {
        case ICMP_ECHO:
            if (ip_addr_isbroadcast(&iphdr->dest, &inp->netmask) ||
                ip_addr_ismulticast(&iphdr->dest)) {
                LWIP_DEBUGF(ICMP_DEBUG, ("Smurf.\n"));
                ICMP_STATS_INC(icmp.err);
                pbuf_free(p);
                return;
            }
            LWIP_DEBUGF(ICMP_DEBUG, ("icmp_input: ping\n"));
            if (p->tot_len < sizeof(struct icmp_echo_hdr)) {
                LWIP_DEBUGF(ICMP_DEBUG, ("icmp_input: bad ICMP echo received\n"));
                pbuf_free(p);
                ICMP_STATS_INC(icmp.lenerr);
                snmp_inc_icmpinerrors();

                return;
            }
            iecho = p->payload;
#if CHECKSUM_CHECK_ICMP
            if (inet_chksum_pbuf(p) != 0) {
                LWIP_DEBUGF(ICMP_DEBUG, ("icmp_input: checksum failed for received ICMP echo\n"));
                pbuf_free(p);
                ICMP_STATS_INC(icmp.chkerr);
                snmp_inc_icmpinerrors();
                return;
            }
#endif
            tmpaddr.addr = iphdr->src.addr;
            iphdr->src.addr = iphdr->dest.addr;
            iphdr->dest.addr = tmpaddr.addr;
            ICMPH_TYPE_SET(iecho, ICMP_ER);
            /* adjust the checksum */
            if (iecho->chksum >= htons(0xffff - (ICMP_ECHO << 8))) {
                iecho->chksum += htons(ICMP_ECHO << 8) + 1;
            } else {
                iecho->chksum += htons(ICMP_ECHO << 8);
            }
            ICMP_STATS_INC(icmp.xmit);
            /* increase number of messages attempted to send */
            snmp_inc_icmpoutmsgs();
            /* increase number of echo replies attempted to send */
            snmp_inc_icmpoutechoreps();

            pbuf_header(p, hlen);
            ip_output_if(p, &(iphdr->src), IP_HDRINCL,
                         IPH_TTL(iphdr), 0, IP_PROTO_ICMP, inp);
            break;
        default:
            LWIP_DEBUGF(ICMP_DEBUG, ("icmp_input: ICMP type %d code %d not supported.\n", (int)type, (int)code));
            ICMP_STATS_INC(icmp.proterr);
            ICMP_STATS_INC(icmp.drop);
    }
    pbuf_free(p);
}

void icmp_dest_unreach(struct pbuf *p, enum icmp_dur_type t)
{
    struct pbuf *q;
    struct ip_hdr *iphdr;
    struct icmp_dur_hdr *idur;

    q = pbuf_alloc(PBUF_IP, 8 + IP_HLEN + 8, PBUF_RAM);
    /* ICMP header + IP header + 8 bytes of data */

    iphdr = p->payload;

    idur = q->payload;
    ICMPH_TYPE_SET(idur, ICMP_DUR);
    ICMPH_CODE_SET(idur, t);

    mips_memcpy((char *)q->payload + 8, p->payload, IP_HLEN + 8);

    /* calculate checksum */
    idur->chksum = 0;
    idur->chksum = inet_chksum(idur, q->len);
    ICMP_STATS_INC(icmp.xmit);
    /* increase number of messages attempted to send */
    snmp_inc_icmpoutmsgs();
    /* increase number of destination unreachable messages attempted to send */
    snmp_inc_icmpoutdestunreachs();

    ip_output(q, NULL, &(iphdr->src),
              ICMP_TTL, 0, IP_PROTO_ICMP);
    pbuf_free(q);
}

#if IP_FORWARD
void icmp_time_exceeded(struct pbuf *p, enum icmp_te_type t)
{
    struct pbuf *q;
    struct ip_hdr *iphdr;
    struct icmp_te_hdr *tehdr;

    q = pbuf_alloc(PBUF_IP, 8 + IP_HLEN + 8, PBUF_RAM);

    iphdr = p->payload;
    LWIP_DEBUGF(ICMP_DEBUG, ("icmp_time_exceeded from "));
    ip_addr_debug_print(ICMP_DEBUG, &(iphdr->src));
    LWIP_DEBUGF(ICMP_DEBUG, (" to "));
    ip_addr_debug_print(ICMP_DEBUG, &(iphdr->dest));
    LWIP_DEBUGF(ICMP_DEBUG, ("\n"));

    tehdr = q->payload;
    ICMPH_TYPE_SET(tehdr, ICMP_TE);
    ICMPH_CODE_SET(tehdr, t);

    /* copy fields from original packet */
    mips_memcpy((char *)q->payload + 8, (char *)p->payload, IP_HLEN + 8);

    /* calculate checksum */
    tehdr->chksum = 0;
    tehdr->chksum = inet_chksum(tehdr, q->len);
    ICMP_STATS_INC(icmp.xmit);
    /* increase number of messages attempted to send */
    snmp_inc_icmpoutmsgs();
    /* increase number of destination unreachable messages attempted to send */
    snmp_inc_icmpouttimeexcds();
    ip_output(q, NULL, &(iphdr->src),
              ICMP_TTL, 0, IP_PROTO_ICMP);
    pbuf_free(q);
}

#endif /* IP_FORWARD */
